Application of Tubular Reactor Technologies for the Acceleration of Biodiesel Production

Abstract

The need to arrest the continued environmental contamination and degradation associated with the consumption of fossil-based fuels has continued to serve as an impetus for the increased utilization of renewable fuels. The demand for biodiesel has continued to escalate in the past few decades due to urbanization, industrialization, and stringent government policies in favor of renewable fuels for diverse applications. One of the strategies for ensuring the intensification, commercialization, and increased utilization of biodiesel is the adaptation of reactor technologies, especially tubular reactors. The current study reviewed the deployment of different types and configurations of tubular reactors for the acceleration of biodiesel production. The feedstocks, catalysts, conversion techniques, and modes of biodiesel conversion by reactor technologies are highlighted. The peculiarities, applications, merits, drawbacks, and instances of biodiesel synthesis through a packed bed, fluidized bed, trickle bed, oscillatory flow, and micro-channel tubular reactor technologies are discussed to facilitate a better comprehension of the mechanisms behind the technology. Indeed, the deployment of the transesterification technique in tubular reactor technologies will ensure the ecofriendly, low-cost, and large-scale production of biodiesel, a high product yield, and will generate high-quality biodiesel. The outcome of this study will enrich scholarship and stimulate a renewed interest in the application of tubular reactors for large-scale biodiesel production among biodiesel refiners and other stakeholders. Going forward, the use of innovative technologies such as robotics, machine learning, smart metering, artificial intelligent, and other modeling tools should be deployed to monitor reactor technologies for biodiesel production.

Keywords: biodiesel; catalyst; feedstock; reactor technologies; transesterification; tubular reactor.

Figure 1

Energy-related CO₂ emissions (billion metric tons).

Figure 2

Ten leading biodiesel producers in 2019.

Figure 3

Global biodiesel production 2016–2022 (billion liters/year).

Figure 4

Transesterification reaction equation.

Figure 5

(a) Schematic representation of a batch-mode reactor. Fabricated batch-mode (b) 20 L; (c) 70 L reactor for biodiesel production. Adapted from [58,59].

Figure 6

Schematic representations of a semi-continuous flow reactor for biodiesel production. Adapted from [62,63].

Figure 6

Schematic representations of a semi-continuous flow reactor for biodiesel production. Adapted from [62,63].

Figure 7

Schematic representations of a continuous flow reactor for biodiesel production. Adapted from [66,67].

Figure 8

Different configurations of static mixers. (a) X-grid static mixer; (b) helical twist static mixer; (c) corrugated plate static mixer.

Figure 9

Packed bed reactor. (a) schematic representation; (b) a packed bed reactor for biodiesel production. Adapted from [72].

Figure 10

(a) schematic representation of a fluidized bed reactor; (b) a typical fluidized bed reactor for biodiesel production. (1 = reactor; 2 = reactor column; 3 = substrate reservoir; 4 = product vessel; 5 and 6 = peristaltic pumps; 7 = thermostatic bath; 8 = reflux condenser). Adapted from [75].

Figure 11

(a) Schematic representation of a trickle bed reactor; (b) a typical trickle bed reactor for biodiesel production. Adapted from [83].

Figure 12

(a) Schematic representation of an oscillatory flow reactor; (b) a typical oscillatory flow reactor for biodiesel production. Adapted from [88].

Figure 13

(a) Schematic representation of a micro channel reactor; (b) a micro channel for biodiesel production. Adapted from [97].